第四课

Unit 2第二单元

Mix and Separation混合与分离

1.We usually flush sugar water, we usually stir; before steaming rice, we wash rice;

冲糖水时，我们通常会搅拌一下;蒸米饭前，我们会淘一淘米;

2.We can also make a variety of drinks according to our own preferences... What is the scientific truth in this?

我们还能根据自己的喜好调制多种口味的饮品......这里面有什么科学道理呢?

four4

How to speed up the dissolution怎样加快溶解

1．When adding salt to the soup, people tend to stir it up.

往汤里加食盐时，人们往往会搅一搅。

2．Why are you doing this?为什么这样做呢?

Material package材料包

1.Coarse salt, fine salt, rock sugar, etc. 粗盐、细盐、冰糖等

Activity process活动过程

1. How to make salt dissolve in water?怎样使食盐在水中加快溶解?

2. I think the mixing would speed up the dissolution. 我认为搅拌会加快溶解。

3. Other conditions should be the same.其他条件要相同。

4. Observe safety when using hot water. 使用热水时注意安全。

5. This is the way we think.这是我们想的办法。

Inquiry skills探究技能

6. Only one experiment with different conditions and the same conditions is called a contrast experiment.

只有一个条件不同，其他条件都相同的实验称为对比实验。

7. Do an experimental study.做个实验研究一下吧。

8. Stir, heating, grinding salt can accelerate the dissolution of salt in water.

搅拌、加热、将食盐研碎等方法可以加快食盐在水中的溶解。

9. See who can make rock sugar dissolve faster in water.

 比一比，看谁能让冰糖在水中溶解得更快。

10. I want to grind the sugar first, then...我想先把冰糖研碎，再......

Expand activities拓展活动

Find a way to speed up the dissolution of matter in life.

找一找人们在生活中加快物质溶解的方法。